Underwater 'lost city' in Greece is actually the aftermath of a gas leak

Divers investigating possible ancient underwater ruinsThe structures were first discovered in 2013 Credit: UNIVERSITY OF EAST ANGLIA

Henry Bodkin

3 June 2016 • 12:20pm

An underwater “lost city” appearing to boast colonnades and courtyards has turned out to be nothing more than the aftermath of a gas leak.

When divers first spotted the structures in shallow water off the Greek island of Zakynthos in 2013 they thought they had discovered the ruins of a long-forgotten civilisation.Zakynthos (Lost City) Map

However, new research published today reveals the site was created by a natural geological phenomenon that took place up to five million years ago in the Pliocene era."This kind of phenomenon is quite rare in shallow waters"Professor Julian Andrews

Scientists from the University of East Anglia joined counterparts at the University of Athens and the Ephorate of Underwater Antiquities of Greece to study the site.

They found that what superficially looked like circular column bases and courtyard floors were actually objects formed by the release of methane from cracks in the sea floor.Marine archaeologists who examined the site (pictured) were unable to find any signs of human activityMarine archaeologists who examined the site were unable to find any evidence of human activity Credit: University of Athens

This natural explanation for the structures was not initially entertained because such gas escapes usually occur at far greater depths.

Professor Julian Andrews, lead author of the study, which is published in the journal Marine Petroleum Geology, said: “The disk and doughnut morphology, which looked a bit like circular column bases, is typical of mineralization at hydrocarbon seeps.Some of the structures formed large doughnut shapes made from dlomite which over time have become covered in algae Some of the structures formed large doughnut shapes made from dlomite which over time have become covered in algae Credit: University of East Anglia

“This kind of phenomenon is quite rare in shallow waters.

“These features are proof of natural methane seeping out of rock from hydrocarbon reservoirs.

“The same thing happens in the North Sea and it is also similar to the effects of fracking.”

The column-like structures and flat 'stone' slabs were formed as a result of a prehistoric gas leak up to five million years ago.Potential underwater ancient ruins but actually a methane structureThe intriguing shapes were caused by leaked methane Credit: UNIVERSITY OF EAST ANGLIA

The process, called concretion, happens when methane gas escapes from a fault and bubbles up through the sediment on the sea floor.

Bacteria living in the sediment metabolises the gas, causing a chemical reaction in the sand around them forming a natural cement known as dolomite.

This solidifies into columns, tubes and slabs and as the surrounding sediment erodes away.

The structures turned out to be natural, rather than man-made. Image Credit: US Navy/Christopher PerezUnderwater ruins off the Greek island of Zakynthos have turned out to be a geological phenomenon.When divers came across an extensive series of courtyards and ruined structures in the shallow waters of the Mediterranean, their first thought was that they'd stumbled on a long-lost civilization.

Now though, following an extensive study of the site, researchers have revealed that the 'ruins' aren't actually man-made at all but are instead the result of a prehistoric gas leak.

Thought to have taken place during the Pliocene era more than 5 million years ago, this extensive release of methane from beneath the sea floor resulted in the formation of structures which, to the eyes of archaeologists, had looked a lot like the ruins of an ancient city.

"The disk and doughnut morphology, which looked a bit like circular column bases, is typical of mineralization at hydrocarbon seeps," said lead study author Professor Julian Andrews.

At the end of the last ice age the sea level was substantially lower. And, since many settlements of antiquity tended to be close to water, would it not be prudent to be looking at about 120m depth for a Neolithic Atlantis.